Today's commercially available metallocene catalyzed very low density polyethylene (VLDPE) resins produced in a gas phase process provide high film toughness (Dart Impact Strength >450 g/mil for a 1 mil monolayer film), but tend to have a number of drawbacks. Due to their narrow molecular weight distributions, these resins have difficulty in conversion to finished products and a tendency for films made from these resins to split in the machine direction. In addition, both the metallocene catalyzed VLDPE resins produced in a gas phase process and the Ziegler-Natta (Z-N) catalyzed VLDPE resins demonstrate non-homogeneous melting of the VLDPE copolymer, i.e. exhibiting at least two peaks in the Differential Scanning calorimetry (DSC) measurement.
A need exists for a single site catalyzed VLDPE resin having high film toughness properties that is relatively easy to process or convert into finished product. Furthermore, a need exists for a VLDPE copolymer that has uniform melting behavior, i.e. exhibiting a single peak in a DSC measurement.